About configuration and effectivity

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Below the result of a discussion 2005-06-28 between Tom T., Tom H. and Lothar. The discussion aspects will be removed in versions of this document.

In the PDM-Usage Guide,Release 4.3 from 23 January 2002 we can find Example 64: "exchange file segment for configuration effectivity".

We analyzed this a little bit further to better understand how the combination of configuration and effectivity to use in practise.

Here the analysis

Available Parts and versions, design (name, id, description):

  • CPU, PR-0133, Pentium II 233
    • A
      • pr1_v1
  • CPU, PR-0146, Pentium II 266
    • C
      • pr2_v1
  • Mainboard, MB-0013, -
    • F
      • mb_v1
  • Power supply unit, PSU-0009, Power supply unit 220V
    • A
      • psu1A_v1
    • B
      • psu1B_v1
  • Power supply unit, PSU-0011, Power supply unit 110V
    • B
      • psua_v1
  • PC system, PC-0023, -
    • D
      • pc_v1

The top assembly tree is: (component name in after "/")

  • PC system, PC-0023, D, pc_v1
    • Power supply unit, PSU-0009, A / psu-u1
    • Power supply unit, PSU-0009, B / psu-u2
    • Power supply unit, PSU-0011, B / psu-u3
    • Mainboard, MB-0013, F / mb-u1
      • CPU, PR-0133, A / cpu-u1
      • CPU, PR-0146, C / cpu-u2

It is clear that this assembly structure contains more power supplies and CPUs than needed. Configuration and effectivity is used to select what belongs actually together. Here the tree of

  • product_concept
    • Configuration_item
      • Configuration_effectivity

in this example:


  • PC model name1, PC-M01
    • Base Config Europe, PC-Conf1, PC system standard configuration for Europe
      • Power supply unit, PSU-0009, A, psu-u1, Start-date=2000-07-01, End-date=1999-03-31
      • Power supply unit, PSU-0009, B, psu-u2, Start-date=1999-04-01, End-date=na
      • CPU, PR-0133, A, cpu-u1, Start-date=2000-10-01, End-date=na Base
    • Config US, PC-Conf2, PC system standard configuration for US
      • CPU, PR-033, A, cpu-u1, SN-start: PS253-000345, SN-end:PS253-000976
      • CPU, PR-0146, C, cpu-u2, SN-start=PS253-000977, SN-end=na
      • Power supply unit, PSU-0011, B, psu-u3, SN-start=PS253-000567, SN-end=na

For both configuration_items there is a configuration_design to the same top product_definition "PC system, PC-0023, D, pc_v1". There is no additional relationship for alternate products.

Here my comments

1) For the European configuration the start and end dates for the power supply makes no sense. They should be corrected for this:

  • Power supply unit, PSU-0009, A, psu-u1, Start-date=1999-03-31, End-date=2000-07-01
  • Power supply unit, PSU-0009, B, psu-u2, Start-date=2000-07-01, End-date=na

<THX>I agree</THX>

2) For both configurations there is no effectivity for the mainboard given. So does the mainboard formally belong to the configuration or not? I can't find an answer to this in the PDM-UG, but the AP203 recommended practices v8 have a clear statement on this in clause

  2.8.15  Effectivity
 "All effectivities in AP 203 are explicit effectivities and there
 are no assumed effectivities.  Some systems in existence today
 assume a part is effective for all planned or actual instances of a
 product model if the effectivity is not explicitly defined.  This is
 not the intent in AP 203. If a part has no effectivity in the AP 203
 data structures, it has no effectivity.  If a part is effective for
 all instances of a product model, the data should explicitly state
 all the effective instances. The effectivities in AP 203 contain
 open ranges for serial numbers and dates to allow for open or full
 effectivities.  Using these constructs, all that is required is a
 start point.  If there is a desire for full effectivity and the
 start point is not defined, the value "1" should be used for the
 serial_numbered_effectivity effectivity_start_id or the equivalent
 date of January 1st year 1 should used for dated_effectivity
 effectivity_start_date."

Following this the examples misses Configuration_effectivity on "Mainboard, MB-0013, F / mb-u1" for both configurations. Do you agree??? <THX>Yes I agree.</THX>

3) In the case that the answer is NO for the above question then we must have a way to express negative effectivities, this is a usage of Configuration_effectivity which makes clear that a particular component is not part of the assembly. This logic would follow the assumption that every component of the product structure belongs to a particular configuration_item unless it is explicitly dropped of. For the given example additional Configuration_effectivity would need to be added to exclude the non needed "Power supply unit"s.

4) Assume the PC system can be equipped with one or two main boards. In this case the configuration has to specify which processor to use for which mainboard. To only way to unambiguously do this in a hierarchical product structure is with specified_higher_usage_occurrence. Do you agree? <THX>I agree.</THX>

5) In this example configuration_design is related to the product_definition_formation of the PC system. In the modules we have now also the possibility to relate it to a product_definition instead. This looks for me the far better approach. Assume you have a very complex assembly, but only a few components needs configuration. Using Part_occurrence we could then have 2 Assembly_definitions (product_definition) for the same Part_version, one with all the details and one with only those components which require configuration. <THX>How would this work in the example? </THX>

6) The given example is clearly what I would call a 150% assembly structure. It would be good to be able to say a particular Assembly_definition is a 100% structure without further analysis of the configuration and effectivity information.

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